Enhanced photocatalytic degradation of a phenolic compounds’ mixture using a highly efficient TiO2/reduced graphene oxide nanocomposite

Abstract

A nanocomposite (namely rGOTi) was prepared by loading 0.33 weight percent of reduced graphene oxide (rGO) on commercial TiO 2 nanoparticles using a hydrothermal method. The as-prepared nanocomposite was characterized using surface and bulk analytical techniques such as X-ray photoelectron spectroscopy, X-ray diffraction, and Fourier transform infrared and Raman spectroscopies. Also, the surface area was measured using the Brunauer-EmmettTeller technique. In addition, the UV-Vis diffuse reflectance spectroscopy measurements have shown that the band gap energy for TiO 2 was lowered from 3.11 to 2.96 eV when it was composited with rGO to form the rGOTi. The kinetics of the degradation of phenol, p-chlorophenol, and p-nitrophenol (separate or mixed) and their intermediates using the as-prepared nanocomposite photocatalyst compared to the bare TiO 2 nanoparticles was tested using UV and Xenon lamps (mainly a visible light source) as photoexcitation sources in the presence and absence of H 2 O 2 . In general, it was revealed that the photocatalytic activity of the rGOTi using a visible light source, in the presence of H 2 O 2 , is significantly higher than that when (1) a UV lamp and/or (2) TiO 2 nanoparticles were used. Also, the presence of H 2 O 2 led to higher degradation rates of all the phenolic compounds regardless the type of photoexcitation source.

Toward an Accurate Spectrophotometric Evaluation of the Efficiencies of Photocatalysts in Processes Involving Their Separation Using Nylon Membranes

“…Further experiments focused on changing the applied pressure during the filtration process of 5 mL of different solutions of rhodamine B and phenol red at different concentrations of 5, 10, and 20 ppm, using a membrane filter (Figure 4a,b). It is worth mentioning that the choice of the concentrations (20 and 10 ppm) was based on the concentrations reported in the literature [7,17,[19][20][21]. A high vacuum (i.e., low pressure and high suction power) enhanced the removal of the dyes in all cases.…”

“…Filtration can be achieved using different types of cellulose filter papers and microporous membranes [1,9,[13][14][15][16][17][18]. Among the commonly used membranes are nylon membranes [7,17,[19][20][21] which will be used in this study.…”

Fast photocatalytic degradation of dyes using low-power laser-fabricated Cu2O–Cu nanocomposites

“…15 H. Al-Kandari shown that the band gap energy for TiO 2 was lowered from 3.11 to 2.96 eV when it was composited with rGO to form the rGOTi. 16 Cuprous oxide (Cu 2 O) is a promising low-cost, narrow bandgap material in visible-light photocatalytic eld. As a typical metal-decient p-type semiconductor with a bandgap between 2.0-2.2 eV, the spectral absorptance of the naturally occurring copper oxide has a bulge at 600 nm and a plateau that falls off at about 700-800 nm, so Cu 2 O can absorb most of the visible light and the theoretical photoelectric conversion efficiency can reach 18%.…”

An efficient eco advanced oxidation process for phenol mineralization using a 2D/3D nanocomposite photocatalyst and visible light irradiations

“…4a) show diffraction patterns of both anatase and rutile phases. The peaks located at 25.4, 37.9, 48.0, 54.0, 55.1, 62.8, 69.1, 70.5 and 75.2° were assigned to the anatase phase (JPDS 21–1272), whereas the peaks assigned to the rutile phase were obtained at 27.5, 36.1 and 41.1° (JPDS 21–1276) 23, 44 . Figure 4e shows two distinctive diffraction peaks: a strong peak located 27.4° with an interlayer spacing of 3.2 Å and a broad peak located at 13.1° with an interlayer spacing of 6.8 Å, which can be indexed to the hexagonal phase of graphitic C 3 N 4 .…”

“…These studies included changing the experimental conditions and synthesis methods of TiO 2 9–13 , metal particle loading 5, 6, 14 and using a co-catalyst 5, 6, 15 . Considerable attention has been focused on utilizing carbonaceous nanomaterials as a support for TiO 2 to improve its photocatalytic performance due to their unique electrical properties and controllable structures 7, 16–23 . An example of these supports is graphitic carbon nitride (g-C 3 N 4 ), which can be obtained from the pyrolysis of nitrogen-rich organic precursors and is considered the most stable allotrope of carbon nitride 14 .…”